mnnis,That seemed to work.I copied in my pin order, spot checked a couple.If pito hadn't mentioned the arrays in the file & what they represented, I woudn't have figured this out.I am not sure why having the 1284 info separate from this file, in the arduino-extras folder, didn't work either.

So, I am moving on. RTC I2C testing next, then finding something I can talk to via SPI, and finally checking out the SD cards.

..the best way to test the spi is to read/write the sdcards.. quite curious how to work with two sdcards in parallel.. ]

Btw, for testing purposes the "Bitlash" is a really useful tool. It takes ~29kB (together with sdfat) and then you must not upload a sketch everytime, when debugging hw (it is a cli_like interpreter/scripting language)..

The same variables all compile okay for writing to the registers earlier in the sketch.

This line is highlighted: Wire.requestFrom(RTC_address, 8 );

Quote

RTC_I2C_test.cpp: In function 'void loop()':RTC_I2C_test:166: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:C:\Program Files\Arduino-0022\libraries\Wire/Wire.h:53: note: candidate 1: uint8_t TwoWire::requestFrom(int, int)C:\Program Files\Arduino-0022\libraries\Wire/Wire.h:52: note: candidate 2: uint8_t TwoWire::requestFrom(uint8_t, uint8_t)RTC_I2C_test.cpp: At global scope:RTC_I2C_test:215: error: expected declaration before '}' token

..as I wrote:1. do not deploy any cap2. if the clock goes fast then start to add a cap. The bigger the cap the slower the clock3. if the clock goes slow (and none cap there) exchange the xtal4. the cap would be typically 0 .. 15pf, but it depends on the xtal usedP.

PS: as far as I can remeber the clock system on arduino works in the way the arduino's internal clock is used (there is a Timer.c for sys time) and the internal clock is synchronised by the external RTC in a specific regular intervals (to be set, e.g. 300sec). The sdfat lib rely on the internal clock..... setSyncProvider(RTC.get); // the function to get the time from the actual RTC if(timeStatus()!= timeSet) Serial.println("Unable to sync with the RTC"); else Serial.println("RTC has set the system time"); setSyncInterval(300); // set the number of seconds between re-sync of time SdFile::dateTimeCallback(dateTime);...You have to link the time through a dateTime() callback function in order to use it with FAT.

@ two sdcards to run in parallel: frankly, not sure the arduino sdfat is prepared for two sdcards connected (two cards selects is not enough, though). Imagine you have two cards, opened, one for read, the second for write. You need 2 buffers, and the sdfat driver in basically two different states (two different instances of the sdfat driver).. It might be a challenge..

@ two sdcards to run in parallel: frankly, not sure the arduino sdfat is prepared for two sdcards connected (two cards selects is not enough, though). Imagine you have two cards, opened, one for read, the second for write. You need 2 buffers, and the sdfat driver in basically two different states (two different instances of the sdfat driver).. It might be a challenge..

My understanding was that the main idea was to be able to support either card -- one might not populate both card holders, but this gave the user the choice of which style. And I gather that given the wealth of pins, it made sense for the hardware to support both simultaneously, even if it's a "future" on the software side.

.. yes, you are right.. I am thinking about the future (as I passed the exercise with one sdcard already..)- how to run both cards simultanously.. maybe the latest sdfat supports more than one card opened.. if not, maybe chan's fatfs..p.

The current version of SdFat can't support multiple SD cards. You could have cards in both sockets and access one at a time by closing all files, and calling sd.init(speed, chipSelect) to switch cards.

I have a development version that mostly works with multiple cards. You can have files open on all cards at the same time.

It uses multiple instances of the SdFat class.

This is what a program that copies a file from one card to another looks like: